当我在 c++ 中使用函数来初始化 sqlite3 时,当它从函数中出来时,句柄为 Null。知道是什么原因造成的吗?我只是将指针作为参数传递。如果我将打开移动到主要功能,它工作正常。会发生什么导致这种情况?是否有隐藏的东西超出范围?
#include <iostream>
#include "sqlite3.h"
using namespace std;
int init_table(sqlite3 *dbH, string db_name)
{
if (sqlite3_open(db_name.c_str(), &dbH) != SQLITE_OK)
{
cout << "Failed to open DB : " << sqlite3_errmsg(dbH) << endl;
abort();
}
else
{
cout << "Opened database: " << db_name << endl;
}
if (sqlite3_exec(dbH, "PRAGMA synchronous = OFF", NULL, NULL, NULL) != SQLITE_OK)
{
cout << "Failed to set synchronous: " << sqlite3_errmsg(dbH) << endl;
}
if (sqlite3_exec(dbH, "PRAGMA journal_mode = WAL", NULL, NULL, NULL) != SQLITE_OK)
{
cout << "Failed to set journal mode: " << sqlite3_errmsg(dbH) << endl;
}
cout << "dbH 2: " << dbH << endl;
}
int main()
{
sqlite3 * dbH;
dbH = NULL;
cout << "dbH 1: " << dbH << endl;
string dbName = "foo1.db";
init_table(dbH, dbName);
cout << "dbH 3: " << dbH << endl;
}
当运行
$ ./a.out
dbH 1: 0
Opened database: foo1.db
dbH 2: 0x5baa048
dbH 3: 0